With a rapid growth of communication technologies, the demand for personal communication has increased greatly. Mobile communication operators need to pay a special attention to all the aspects directly influencing the mobile service effects, such as user interface, quality of service (QoS) and so on. The characteristics of a 3G mobile communication system, such as a broad bandwidth, multiple services and a high quality, have already been attracting the market of the mobile communication. However there are still some problems existing in the 3G technologies. If these problems can not be solved effectively, the enlargement of 3G market will be constrained in a certain extent, and the development of the mobile operation business will also be affected.
Wideband Code Division Multiple Access (WCDMA) mobile communication system of the 3G technologies is composed of a Core Net (CN), a Universal Mobile Telecommunications System/Universal Mobile Telecommunication System/Universal Mobile Telecommunication Services (UMTS) Terrestrial Radio Access Network (UTRAN) and a User Equipment (UE). In the network architectures after WCDMA R4, the CN is not limited to a circuit switching mode. Instead, the packet switching mode, such as Asynchronous Transfer Mode (ATM), and Internet Protocol (IP), can be chosen as its bearer. The packet switching mode can not only improve the transmission speed of a network, enrich the service category of the network, but also facilitate the management and design of the network architecture. At the same time, in order to realize a separation of the call control and the bearer control, a Mobile Switching Center (MSC) can be divided into two parts: an MSC Server and a Media Gateway (MGW), wherein the MSC Server implements functions of calling control and mobility management while the MGW implements functions of bearer control and data transmission. The interface between the MSC Server and the MGW is called Mc interface, which adopts H.248 as its bearer control protocol.
In a Next Generation Network (NGN) configuration, Public Land Mobile Network (PLMN) including the above WCDMA mobile communication system also needs to carry out the function of interworking with other networks, such as Public Switch Telephone Network (PSTN) or Integrated Service Digital Network (ISDN), wherein the maintenance of a signaling interface between a 3G mobile network and other networks is implemented by the MSC, and the functions of data forwarding and resource channel establishment is implemented by the MGW.